@article{Michalko2022,
title = {Changes of Endophytic Bacterial Community in Mature Leaves of Prunus laurocerasus L. during the Seasonal Transition from Winter Dormancy to Vegetative Growth},
author = {Jaroslav Michalko and Juraj Medo and Peter Ferus and Jana Konôpková and Dominika Košútová and Peter Hot’ka and Marek Barta},
doi = {10.3390/plants11030417},
issn = {2223-7747},
year = {2022},
date = {2022-02-03},
journal = {Plants},
volume = {11},
pages = {417},
abstract = {Diverse communities of bacterial endophytes inhabit plant tissues, and these bacteria play important roles for plant growth and health. Cherry laurel (Prunus laurocerasus L.) is a broadleaf evergreen shrub that is widely grown in temperate zones for its ornamental and medicinal properties, however virtually nothing is known about its associated bacterial community. In this study, we analysed the matured one-year-old leaves of this plant using Illumina-based 16S rRNA gene metabarcoding to reveal the community structure of endophytic bacteria and understand its shifts during the seasonal transition from winter dormancy to a spring vegetative state. The overall community was composed of four dominant phyla (Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes). Corynebacterium, Acinetobacter, and Chryseobacterium genera were the most prevalent bacteria, comprising 13.3%, 6.9%, and 6.8% of the amplicon sequence variants (ASVs), respectively. The ASV richness and diversity increased significantly in May as compared to other sampling months (February, March, and April). We observed high variation in the overall community structure of endophytic bacteria among collection dates. The variation was only reflected by a few core community members, suggesting that the changes of the endophytic community during winter/spring seasonal transition are mostly associated with the less abundant community members. We identified biomarker taxa for late winter, mid spring, and late spring collection dates. This study is the first one to report on the diversity and composition of bacterial endophytes in the leaves of cherry laurel and its shifts across the dormancy-to-vegetative seasonal transition.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Tvrdá2020,
title = {Characterization of the Omija (\textit{Schisandra chinensis}) Extract and Its Effects on the Bovine Sperm Vitality and Oxidative Profile during \textit{In Vitro} Storage},
author = {Eva Tvrdá and Jaroslav Michalko and Július Árvay and Nenad L. Vukovic and Eva Ivanišová and Michal Ďuračka and Ildikó Matušíková and Miroslava Kačániová},
doi = {10.1155/2020/7123780},
issn = {1741-427X},
year = {2020},
date = {2020-09-22},
journal = {Evidence-based Complementary and Alternative Medicine},
abstract = {Schisandra chinensis is a woody vine native to China, Korea, and Russia, which has been used as a traditional herbal remedy to treat male infertility. As very little information is available concerning its effects on ejaculated spermatozoa, the aim of this study was to investigate the chemical, antioxidant, and antibacterial properties of the S. chinensis berry (Omija) extract followed by an assessment of its in vitro effects on bovine sperm function and oxidative balance. Phytochemical components of the Omija extract were determined by high performance liquid chromatography. The content of polyphenols, flavonoids, and carotenoids was assessed by spectrophotometric protocols. Antioxidant characteristics of the Omija extract were determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and molybdenum-reducing antioxidant power (MRAP) assays. The disc diffusion method and determination of the minimal inhibitory concentration were applied to study the antibacterial properties of Schisandra. Thirty semen samples were exposed to different concentrations of Omija (1, 5, 10, 25, 50, and 75 µg/mL) for 0, 2, and 24 h. Sperm motility, mitochondrial activity, and superoxide and reactive oxygen species production, as well as total antioxidant capacity and oxidative damage to proteins and lipids were determined. Our data reveal that the Omija extract, particularly at a concentration range within 5–50 µg/mL, exhibited dose-dependent motion-promoting and metabolism-enhancing properties, accompanied by significant antioxidant effects. We may conclude that the biomolecules present in the Omija extract such as schisandrins and phenolic molecules offer protection to critical sperm structures against oxidative insults and/or possible bacterial contamination, leading to a higher preservation of mammalian sperm viability and functional activity.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Pundiak2020,
title = {\textit{Epiphyllous bryophytes} in Arboretum Mlyňany (Slovakia)},
author = {Oleh Pundiak and Jaroslav Michalko},
doi = {10.15414/AFZ.2020.23.02.51-57},
issn = {1335-258X},
year = {2020},
date = {2020-06-30},
journal = {Acta fytotechnica et zootechnica},
volume = {23},
number = {2},
pages = {51-57},
abstract = {In this work we screened for the diversity of epiphyllous bryophytes covering leaves of evergreen plants growing in temperate region of Arboretum Mlyňany (Slovakia). We identified five taxa of not typically epiphyllous bryophytes, all belonging to mosses: Brachythecium salebrosum (Hoffm. ex F. Weber & D. Mohr) Schimp, Hypnum cupressiforme Hedw., Hypnum cupressiforme var. filiforme Brid., Platygyrium repens (Brid.) Schimp., Pylaisia polyantha (Hedw.) Schimp. All these taxa are considered as obligate members of bryoflora of Slovakia at low risk of extinction. The most abundant was the generalist H. cupressiforme, while the rarest was the typical epiphyte P. polyantha. All identified epiphylls occurred on nine species of evergreen angiosperm phorophytes: Prunus laurocerasus L., Hedera helix L., Mahonia aquifolium (Pursh) Nutt., Ilex aquifolium L., Rubus caesius L., Viburnum × burkwoodii auct., Rhododendron catawbiense Michx., Viburnum rhytidophyllum Hemsl., Aucuba japonica Thunb.; on one gymnosperm phorophyte Cephalotaxus harringtonii var. drupacea (Siebold. & Zucc.) Koidz; and on one fern Asplenium scolopendrium L. The most often species of phorophyte for epiphyllous bryophytes was P. laurocerasus, while the rarest taxa were R. caesius, V. rhytidophyllum, R. catawbiense, A. japonica, V. × burkwoodii.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Tvrdá2016,
title = {In vitro effects of the \textit{Chlamydomonas reinhardtii} extract on bovine spermatozoa [In vitro účinok extraktu riasy \textit{Chlamydomonas reinhardtii} na hovädzie spermie]},
author = {Eva Tvrdá and Jaroslav Michalko and Ildikó Matušíková and Norbert Lukáč},
doi = {10.15414/jmbfs.2016/17.6.3.972-975},
issn = {1338-5178},
year = {2016},
date = {2016-12-01},
journal = {Journal of Microbiology, Biotechnology and Food Sciences},
volume = {6},
number = {3},
pages = {972-975},
abstract = {In vitro storage and processing of animal semen is represents a risk factor to spermatozoa vitality, potentially leading to reduced fertility. A variety of substances isolated from natural sources may exhibit protective or antioxidant properties on the spermatozoon, thus extending the lifespan of stored ejaculates. Chlamydomonas has been shown to possess antimicrobial, anti-inflammatory and antioxidant properties, turning the extract into a potential candidate for preserving liquid animal semen during in vitro storage. This study compared the ability of different concentrations of the Chlamydomonas reinhardtii extract on the motility, viability and superoxide production of bovine spermatozoa during different time periods (0, 2, 6, 12 and 24h) of in vitro culture. Spermatozoa motility was assessed using the SpermVisionTM CASA (Computer aided sperm analysis) system. Cell viability was examined using the metabolic activity MTT assay and the nitroblue-tetrazolium (NBT) test was applied to quantify the intracellular superoxide formation. The CASA analysis revealed that the Chlamydomonas extract supplementation was able to prevent a rapid decline of spermatozoa motility, especially in the case of concentrations ranging between 1 and 5 µg/mL (P<0.001 with respect to Times 6h, 12h and 24h). At the same time, concentrations ranging between 5 and 10 µg/mL of the extract led to a significant preservation of the cell viability throughout short-term (P<0.05 in case of Time 6h) as well as long-term periods of the experiment (P<0.01 with respect to Time 12h, and P<0.001 in case of Time 24h). 5 and 10 µg/mL of the extract exhibited antioxidant characteristics, translated into a significant reduction of the intracellular superoxide production, particularly notable at Times 12h (P<0.01 with respect to10 µg/mL and P<0.05 in case of 5 µg/mL) and 24h (P<0.01). The results indicate that the Chlamydomonas extract is capable of delaying the damage inflicted to the spermatozoon by the in vitro environment.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Medo2016,
title = {Phylogenetic structure and habitat associations of Beauveria species isolated from soils in Slovakia},
author = {Juraj Medo and Jaroslav Michalko and Janka Medová and Ľudovít Cagáň},
doi = {10.1016/j.jip.2016.08.009},
year = {2016},
date = {2016-10-01},
journal = {Journal of Invertebrate Pathology},
volume = {140},
pages = {46-50},
abstract = {The phylogenetic structure of 109 soil-borne entomopathogenic Beauveria isolates acquired using the Galleria mellonella bait method from different habitat types in Slovakia was determined by sequence analysis of their ITS and Bloc loci. Three Beauveria species were identified; Beauveria bassiana, B. pseudobassiana and B. brongniartii, represented by 51.4%, 43.1% and 5.5% of acquired isolates, respectively, which were resolved into 15, 1 and 1 distinguishable haplotypes. Correlation analysis with the habitat type and individual habitat characteristics showed strong preferences of the most prevalent haplotypes for agricultural (B. bassiana A1) and forest habitats (B. pseudobassiana) which has possible implications for conservative biocontrol strategies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}